Timing Gear

[corey]

Merry Christmas everyone! Hope everyone is enjoying time with family / friends / whomever this season. Since the GMC is now part of our family, I've
been spending plenty of time with it this week too. While the fuel pump is out I tried to get in and see whether the timing gears have been upgraded
from the nylon cam gear. The borescope I have does not have the best picture quality so the best I could do is go in with a mirror. Still it's
difficult to get enough light and your eye lined up well enough to get a good look. The best way to do it was put my phone camera with flash on up to
the hole. The chain appears to be OEM type, but I know there are aftermarket sets with original style chain but with all-metal cam gear. I Got a
pretty good shot of the gear teeth, and I THINK they are metal but I guess I've never seen one of the nylon tipped gears in person. I would much
appreciate the expert eyes of those of you that have seen these nylon gears before. The video is here: https://youtu.be/Gqvk4Y05R4Q . Thanks!
--
Corey P /

Hilliard, OH /

1974 Glacier 26'

ION Wheels

 

[Melbo]

I would agree with you that you have a fully metal cam gear. Mine is orange by the teeth. The nylon is white when it comes off if I remember
correctly from 48 years ago when I changed them on pontiac motors. The nylon is easy to identify from the metal.

One less thing to fix is a good thing.

Melbo
--
Albuquerque NM Bus Conversion 1978 MCI 1973 GMC

 

[Matt Colie]

Corey,

I am not at my desk and don't have a keyboard, but were I you,I would inspect the engine front. If the timing cover, front mount and related parts do
not appear to have disturbed, I would take that as proof that the timing set is still OE.

The chain set that I put in was still not a roller set, so visual inspection would be difficult, but in my case, the build bok will tell a lot.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

 

[Jim Hupy]

It is an original equipment style timing chain set. If you look closely at
your picture, you can see the teeth on the camshaft sprocket. They are
metal, not plastic. They may have been there since the coach was new, or
they could have been replaced somewhere along the way. No way to tell from
here. They could be within service limits, or not. You have already been
told how to check it. So, I won't repeat that.
Jim Hupy
Salem, Oregon

On Wed, Dec 25, 2019, 10:31 AM Matt Colie via Gmclist <

> Corey,
>
> I am not at my desk and don't have a keyboard, but were I you,I would
> inspect the engine front. If the timing cover, front mount and related
> parts do
> not appear to have disturbed, I would take that as proof that the timing
> set is still OE.
>
> The chain set that I put in was still not a roller set, so visual
> inspection would be difficult, but in my case, the build bok will tell a
> lot.
>
> Matt
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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[corey]

Most of the engine has about 85% of its blue paint left on it. The water pump and timing cover behind it have none. This tells me they've both been
off / replaced
--
Corey P /

Hilliard, OH /

1974 Glacier 26'

ION Wheels

 

[Matt Colie]

> Most of the engine has about 85% of its blue paint left on it. The water pump and timing cover behind it have none. This tells me they've both
> been off / replaced

Corey,

That sure looks a lot like the timing gear set I recently installed. It is also about the only reason someone would bother the timing gear cover.

I think you won this one.....

Matt - Back from Christmas dinner with the daughter and family.
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit